Locomotive Couplings

[ron]

Hi All
What is the normal method of coupling a passenger hauling model loco to a driving car, the plans for the Simplex I'm building show a 'scale' coupling which doesn't look man enough for the job, in fact it looks so flimsy I have visions of sitting on a driving car watching the loco disappearing off down the line!!

Hope you all had an enjoyable Xmas

Ron

[greasemonkey]

Hi Ron
It largely depends upon your club. I believe the Southern Fed insurance requires welded links in any chain. A lot of clubs now require solid bars which is my prefrence for passenger pulling and some even now ask for saftey chains as well. I certainly dont like scale couplings for anything but exhibitions on the rear buffer beams,a clevis is a better bet all round. Just my opinions what do others do?

Andy

[baggo]

Hi Ron,

I think the standard fitting nowadays is the clevis securely bolted to the rear buffer beam and a similar one on the driving trolley. The actual coupling is just a flat piece of bar with a hole in each end and secured with a vertical pin into each clevis. As Andy says, some clubs insist on a safety chain fitted as well in case the coupling comes adrift. There's no reason not to fit a 'scale' coupling to the front buffer beam unless you want to run bunker first!
Funny enough, I was thinking a while ago as to why a safety shut off valve could not be fitted in the steam pipe after the regulator. The valve would be spring loaded and held open by a pin. The pin would have a cord attached to it and the driving trolley. If the trolley and loco parted company the pin would be pulled out and the spring loaded steam valve would shut and cut off the steam thus stopping the loco. Bit like a dead mans handle! Probably a bit over the top but food for thought in these increasingly safety conscious days.

John

Coudn't find a photo of the loco end but here's one of a trolley end. The coupling bar can be altered in height to suit different locos by moving the spacers up or down and centred with the adjustable stay



Found one of the coupling on a 2-1/2" Black Five

[Chris Kelland]

Hi Ron, and All,

This may not go according to plan, but I have a photo of the coupling on my Simplex which I will try to get onto my post.

Chris.




Wonderful, it works! so to celebrate a full side view of the Simplex!

[ron]

Thanks for the replies, I'll make something similar to what's suggested. I'm surprised there isn't a standard, must make it a bit awkward if you're visiting somewhere without your own truck?
Ron

[Chris Kelland]

In pratice there is not usually a problem, at our Oxford Rally each year (Dreaming Spires) we get about 50 loco's over the 2 days and I can't recall any problems. The only problem is trying to use a 5 inch loco with 7 1/4 rolling stock.


Chris K.

[jackrae]

Och man, Just use a bit of knicker elastic

One of the problems of using a rigid bar fitted between forks on engine and riding truck can arise when the two forks are not in alignment with each other - frequently encountered when using different gauges of engine and riding car..

During deceleration the bar, attempts to rotate about the two pivot pins and will exert a side thrust on the forks which can, in extreme circumstances, lead to a tendency to derail either engine or riding truck.

Such effect can be readily overcome by making the coupling bar out of two shorter bars, joined by another pivot pin. During deceleration the bar then "bends" about its own pivot pin without exerting any side thrust on the engine or riding car.

Happy new year to all

Jack

[Laurie_B]

Hello Chris,Very nice Simplex!
Bit off topic,but I was also interested in the image on the wall above the Simplex.Looks like someone has a BR Class 2 under construction?I seem to recognise that pony truck 'A' frame!
The fittings look quite detailed too.
Would you have any more info as I'm presently building a 5" gauge Class 2?

[greasemonkey]

Hi Jack
Surely if your train is decelerating that quickly you have got the brakes on and the tie bar will still be in tension. In full size practise the loco hauls the train but the train stops the loco! I have never had the problem you describe, if we are all building to the same standards then the coupling centres should be the same.
happy new year

Andy

[stantheman]

Hi all.
This chat about couplings reminds me of a very nasty experience I once had. While driving my locomotive round at a South Wales track many years ago I unfortunately ran into a piece of rock that some idiot had jammed in between a couple of the rails. My locomotive, a modified 'Pansy', was derailed so severly it ended up on the ground nose first. Due to the fact I did then, and still do, use a stout chain coupling, my driving car along with myself and Wife remained safely up on the track. It was suggested that if I had been using a solid bar coupling things may have been a little different.
At our own club we do use heavy chain couplings between the passenger cars and our driving cars, each secured through a heavy piece of channel with fixed pins, never had a problem yet. Only thing we watch is when setting off we do not 'snatch' the chain to heavily.
Stan.

[greasemonkey]

Hi Stan
I have had the opposite experience and had the tender of my engine derail, if it were not for a bar it would have had the lot of. I think you just make your decision about which you are happiest. If the engine is big enough I dont think it will make much diffrence.

Andy

[baggo]

Hi Stan,
that reminds me of a similar incident at the 2½ gauge rally at Rugby this year but sort of in reverse. Andrew Dick was driving his 2½" Josie around the track and for some reason stopped and lent over to look at something under the raised track. He overbalanced and the driving trolley toppled over and deposited him on the ground. Because the coupling bar between the driving trolley and loco was solid this fetched the loco and tender off the track as well! Maybe these solid bar couplings are not such a good idea after all

John

[stantheman]

Andy, absolutely.
Safety for yourself comes first along with that of your own locomotive and those around you.
Raised tracks do make a mess of inner thighs if it all goes wrong and it comes a cropper.
Stan.

[chameleonrob]

jackrae said:

One of the problems of using a rigid bar fitted between forks on engine and riding truck can arise when the two forks are not in alignment with each other - frequently encountered when using different gauges of engine and riding car..

During deceleration the bar, attempts to rotate about the two pivot pins and will exert a side thrust on the forks which can, in extreme circumstances, lead to a tendency to derail either engine or riding truck.

I've had that problem but not when breaking but when reversing back from our station to the shed up a very steep hill, the harder the loco pushed the train the harder the flanges gripped the rail until I slid to a stop, and when back the long way round.

If it is a consistent problem then longer coupling bars can work, I wouldn't use chain coupling (of any size) simply because it means that all the stock would have to have compatible buffers, ignoring visiting locos that would be hard as we have scale 5" locos standard gauge and 7 1/4" narrow gauge locos on the same carriages.

rob

[steamjohn248]

Re Couplings. probably not of much interest to scale modelers but our NG type stock is connected bogie pivot to bogie pivot by a bar (or rather pair of bars). Thus with a vacuum braked train regardles of the efficiency of individual bogies/brakes, the braking effort is spread throughout the train. We reckon its the nearest you can get to buckeyes but a lot cheaper. The connection between the pairs of bars is a thick square of conveyor belting sandwiched between four 5mm by 50 mm strips 90mm long, the upper ones welded to the ends of the bars, (crossways), the whole lot secured by four M8 bolts with self locking nuts. Thus we dont get a tendency to shove things sideway when the stock is pushing the loco or vice versa and in the unlikely event of a bogie "going into the dirt" everything stays upright and ,as already stated, the whole train is braking the loco not the other way round.

Since we are essentially a commercial railway with train weights up to three tons we think this all makes sense though accept that in comparison with club tracks and private lines we may be overdoing it. (and yes we do provide 'adaptors' for visiting locos but never use any form of chain except for a pair of safety chains between loco and driving car,

John

[Chris Kelland]

Hi Laurie_B & All,

Thanks for the kind remark about my Simplex. Look closely and you will see it has a hard life on passenger work.

You may well be right about the Class 2, but the chap I need to talk to is still in the States.

A happy New Year to all of you,

Regards,


Chris.